1. Field of the Invention
This invention relates to a catalyst and process for hydrodesulfurization of mineral oils. More particularly, this invention relates to a catalyst comprising a hydrogenation component composited with an alumina support characterized by a unique solid state structure resulting from its method of preparation.
2. Description of the Prior Art
Hydrodesulfurization processes in which heavy hydrocarbon distillates or residual fractions are hydrotreated with hydrogen in the presence of a catalyst comprising a hydrogenation component composited with a refractory oxide support, such as alumina, are well known (see, for example, U.S. Pat. No. 3,531,398; U.S. Pat. No. 3,509,044 and U.S. Pat. No. 3,770,618).
Hydrodesulfurization catalysts having specified physical characteristics such as pore size distribution have been proposed to overcome disadvantages of conventional prior art catalysts.
U.S. Pat. No. 3,876,523 discloses a hydrodemetallization and hydrodesulfurization alumina base catalyst having an average pore diameter between 150 to 250 Angstroms.
U.S. Pat. No. 3,891,541 discloses a demetallization and desulfurization catalyst comprising a hydrogenation component composited with an alumina support, the pores of which are distributed over a narrow 180 to 300 Angstrom diameter range and having a surface area in the range of 40 to 70 m.sup.2 /g.
U.S. Pat. No. 3,393,148 discloses a hydroprocessing catalyst comprising a hydrogenation component and a large pore diameter alumina having a surface area ranging from 150 to 500 m.sup.2 /g and an average pore diameter ranging from 100 to 200 Angstroms.
U.S. Pat. No. 3,471,399 discloses a hydrodesulfurization catalyst comprising silica-alumina and a hydrogenation component, said catalyst having an average pore diameter ranging from 70 to 90 Angstroms and a surface area of about 150 to 250 square meters.
U.S. Pat. No. 3,322,666 discloses a hydrodesulfurization catalyst comprising a hydrogenation component and an activated alumina having less than 5 percent of its pore volume, that is in the form of pores having a radius of 0 to 300 Angstroms and less than 10 percent of its pore volume in pores larger than 80 Angstrom radius.
It has now been found that a hydrodesulfurization catalyst comprising an alumina carrier having a specific solid state structure resulting from the method of its preparation provides advantages that will become apparent in the ensuing description.